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These first two animations illustrate the shapes of two molecules that have the same tetrahedral bonding structure. However, because oxygen can form only two bonds, water molecules are asymmetrical, while methane molecules are completely symmetrical.

The asymmetry of water molecules enables them to form hydrogen bonds with each other, and build "water structure." Oils, built from carbon and hydrogen, cannot form hydrogen bonds, and are excluded from water.

Glucose and fructose readily inter-convert. The reaction is greatly enhanced by the appropriate enzyme. At equilibrium, the mixture is close to, but not quite, a 1:1 mix of glucose and fructose. This is what high-fructose corn syrup is (and also honey, agave nectar, etc).

These three animations illustrate molecule motion under different conditions. The important point is that in the gas phase, molecules are farther apart, and move more rapidly than in liquid or solid. At higher temperatures, the molecules are even farther apart, and move even faster.